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Chapter 13 The Peripheral Nervous System & Reflex

Chapter 13 The Peripheral Nervous System & Reflex
94問 • 1年前
  • Bear4
    • 通報

    問題一覧

  • 1

    PNS provides links from & to world outside our body

    Consists of all neural structures outside brain & spinal cord that can be broken down into four parts

  • 2

    PNS provides links from & to world outside our body

    Part 1 – Sensory Receptors, Part 2 – Transmission Lines: Nerves & Their Structure & Repair, Part 3 – Motor Endings & Motor Activity, Part 4 – Reflex Activity

  • 3

    specialized to respond to changes in environment (stimuli)

    Sensory Receptors

  • 4

    Activation results in graded potentials that trigger nerve impulses

    Sensory Receptors

  • 5

    Three ways to classify receptors:

    type of stimulus, body location, structural complexity

  • 6

    respond to touch, pressure, vibration, & stretch

    Mechanoreceptors

  • 7

    sensitive to changes in temperature

    Thermoreceptors

  • 8

    respond to light energy (example: retina)

    Photoreceptors

  • 9

    respond to chemicals (examples: smell, taste, changes in blood chemistry)

    Chemoreceptors

  • 10

    sensitive to pain-causing stimuli (examples: extreme heat or cold, excessive pressure, inflammatory chemicals)

    Nociceptors

  • 11

    Respond to stimuli arising outside body –Receptors in skin for touch, pressure, pain, & temperature –Most special sense organs

    Exteroceptors

  • 12

    Respond to stimuli arising in internal viscera & blood vessels –Sensitive to chemical changes, tissue stretch, & temperature changes –Sometimes cause discomfort but usually person is unaware of their workings

    Interoceptors (Visceroceptors)

  • 13

    Respond to stretch in skeletal muscles, tendons, joints, ligaments, & connective tissue coverings of bones & muscles –Inform brain of one's movements

    Proprioceptors

  • 14

    Modified dendritic endings of sensory neurons ●Are found throughout body & monitor most types of general sensory information –General Senses: Tactile Sensations (Touch, Pressure, Stretch, Vibration), Temperature, Pain, & Muscle Sense •No “one-receptor-one-function” relationship •Receptors can respond to multiple stimuli

    Simple receptors of the General Senses

  • 15

    All are housed in complex sense organs –Vision, Hearing, Equilibrium, Smell, & Taste

    Receptors for Special Senses

  • 16

    Most are Non-Myelinated & abundant in epithelia/connective tissues –Respond mostly to temperature, pain, or light touch

    Non-Encapsulated (free) Nerve Endings

  • 17

    Located in superficial Dermis –Cold receptors are activated by temps from 10 to 40C –Heat receptors are activated from 32 to 48C located in in deeper dermis •Outside those temperature ranges, nociceptors are activated & interpreted as pain

    Thermoreceptors

  • 18

    pain receptors triggered by extreme temperature changes, pinch, or release of chemicals from damaged tissue –Vanilloid receptor: protein in nerve membrane is main player •Acts as ion channel that is opened by heat, low pH, chemicals (example: capsaicin in red peppers) •Itch receptors in dermis: can be triggered by chemicals such as histamine

    Nociceptors

  • 19

    Non-Encapsulated (Free) Nerve Endings (2answers)

    Tactile (Merkel) Discs, Hair Follicle Receptors

  • 20

    function as light touch receptors ●Located in deeper layers of epidermis

    Tactile (Merkel) Discs

  • 21

    free nerve endings that wrap around hair follicles ●Act as light touch receptors that detect bending of hairs –Ex: Allows you to feel a mosquito landing on your skin

    Hair Follicle Receptors

  • 22

    Most body tissues; most dense in connective tissues (ligaments, tendons, dermis, joint capsules, periostea) and epithelia (epidermis, cornea, mucosae, and glands)

    Free nerve endings of sensory neurons

  • 23

    Basal layer of epidermis

    Modified free nerve endings: Epithelial tactile complexes (Merkel cells and discs)

  • 24

    Surrounding hair follicles

    Hair follicle receptors

  • 25

    Encapsulated Dendritic Endings (2answers)

    Tactile (Meissner’s) corpuscles, Lamellar (Pacinian) corpuscles

  • 26

    Almost all (Encapsulated Dendritic Endings) are _______ whose terminal endings are encased in _______

    Mechanoreceptors, connective tissue capsule

  • 27

    Almost all are Mechanoreceptors whose terminal endings are encased in connective tissue capsule

    Encapsulated Dendritic Endings

  • 28

    small receptors involved in discriminative touch –Found just below skin, mostly in sensitive & hairless areas (fingertips)

    Tactile (Meissner’s) corpuscles

  • 29

    large receptors respond to deep pressure & vibration when first applied (then turn off) –Located in deep dermis

    Lamellar (Pacinian) corpuscles

  • 30

    respond to deep & continuous pressure - Located in dermis

    Bulbous Corpuscles (Ruffini Endings)

  • 31

    spindle-shaped proprioceptors that respond to muscle stretch

    Muscle Spindles

  • 32

    proprioceptors located in tendons that detect stretch

    Tendon Organ

  • 33

    proprioceptors that monitor joint position & motion

    Joint Kinesthetic Receptors

  • 34

    Dermal papillae of hairless skin, particularly nipples, external genitalia, fingertips, soles of feet, eyelids

    Tactile (Meissner's) corpuscles

  • 35

    Dermis and hypodermis; periostea, mesentery, tendons, ligaments, joint capsules; most abundant on fingers, soles of feet, external genitalia, nipples

    Lamellar (Pacinian) corpuscles

  • 36

    Survival depends upon ____ & ____.

    Sensation, Perception

  • 37

    awareness of changes in the internal & external environment

    Sensation

  • 38

    the conscious interpretation of those stimuli

    Perception

  • 39

    part of sensory system serving body wall & limbs

    Somatosensory System

  • 40

    Input is relayed _____ head, but processed along the way

    toward

  • 41

    Somatosensory System: part of sensory system serving body wall & limbs •Receives inputs from

    Exteroceptors, Proprioceptors, Interoceptors

  • 42

    (Somatosensory System) Levels of neural integration in sensory systems: (3answers)

    Receptor level, Circuit level, Perceptual level

  • 43

    sensory receptors

    Receptor level

  • 44

    processing in ascending pathways

    Circuit level

  • 45

    processing in cortical sensory areas

    Perceptual level

  • 46

    (Processing at the Receptor Level) For sensation to occur, the stimulus must excite a receptor, & the AP must reach CNS

    Generating a signal

  • 47

    Stimulus energy must match receptor specificity (touch receptors do not respond to light) ●Stimulus must be applied within receptive field

    Generating a signal

  • 48

    must occur—energy of stimulus is converted –Generator Potential (in general receptors) or receptor potential (in special sense receptors): graded potential •Graded potentials must reach threshold → AP

    Transduction

  • 49

    Change in sensitivity in presence of constant stimulus

    Adaptation

  • 50

    -Receptor membranes become less responsive -Receptor potentials decline in frequency or stop

    Adaptation

  • 51

    fast-adapting, send signals at beginning or end of stimulus ●Ex: receptors for pressure, touch, & smell

    Phasic Receptors

  • 52

    slow adapting or not at all ●Ex: nociceptors & most proprioceptors

    Tonic Receptors

  • 53

    Pathways of 3 neurons conduct sensory impulses from receptors upward to appropriate cortical regions

    Processing at the Circuit Level

  • 54

    Processing at the Circuit Level –Pathways of 3 neurons conduct sensory impulses from receptors upward to appropriate cortical regions (3answers)

    First-Order Sensory Neurons, Second-Order Sensory Neurons, Third-Order Sensory Neurons

  • 55

    Conduct impulses from receptor level to spinal reflexes or second-order neurons in CNS

    First-Order Sensory Neurons

  • 56

    Transmit impulses to third-order sensory neurons

    Second-Order Sensory Neurons

  • 57

    Conduct impulses from thalamus to the somatosensory cortex (perceptual level)

    Third-Order Sensory Neurons

  • 58

    Interpretation of sensory input depends on specific location of target neurons in sensory cortex

    Processing at the Perceptual Level

  • 59

    ability to detect a stimulus (requires summation of impulses)

    Perceptual Detection

  • 60

    ●Felt as vague aching, gnawing, burning ●Activated by tissue stretching, ischemia, chemicals, muscle spasms

    Visceral Pain - visceral organ receptors

  • 61

    pain from one body region perceived as coming from different region ●Visceral & Somatic Pain fibers travel along same nerves, so brain assumes stimulus comes from common (somatic) region –Ex: left arm pain during heart attack

    Referred Pain

  • 62

    Long-lasting or intense pain, such as limb amputation, can lead to __(1)__ (pain amplification), chronic pain, & ___(2)___

    (1) Hyperalgesia, (2) Phantom Limb Pain

  • 63

    receptors are activated by long-lasting or intense pain

    NMDA

  • 64

    pain felt in limb that has been amputated –Now use epidural anesthesia during surgery to reduce phantom pain

    Phantom Limb Pain

  • 65

    cordlike organ of PNS

    Nerve

  • 66

    Bundle of myelinated & nonmyelinated peripheral axons enclosed by

    connective tissue

  • 67

    Two types of nerves:____or ____depending on where they originate

    spinal, cranial

  • 68

    Endoneurium/Neurilemma

    loose connective tissue that encloses axons & their myelin sheaths (Schwann cells)

  • 69

    Perineurium

    coarse connective tissue that bundles fibers into Fascicles

  • 70

    Epineurium

    tough fibrous sheath around all fascicles to form the nerve

  • 71

    contain both sensory & motor fibers ●Impulses travel both to & from CNS

    Mixed Nerves

  • 72

    impulses only toward CNS

    Sensory (Afferent) Nerves

  • 73

    impulses only away from CNS

    Motor (Efferent) Nerves

  • 74

    are rare; most nerves are mixed

    Pure Sensory (Afferent), Pure Motor (Efferent) Nerves

  • 75

    Types of fibers in______ -Somatic Afferent (sensory from muscle to brain) -Somatic Efferent (motor from brain to muscle) -Visceral Afferent (sensory from organs to brain) -Visceral Efferent (motor from brain to organs)

    Mixed Nerves

  • 76

    sensory from muscle to brain

    Somatic Afferent

  • 77

    motor from brain to muscle

    Somatic Efferent

  • 78

    sensory from organs to brain

    Visceral Afferent

  • 79

    motor from brain to organs

    Visceral Efferent

  • 80

    contain neuron cell bodies associated with nerves in PNS

    Ganglia

  • 81

    Ganglia associated with _____contain cell bodies of Sensory Neurons -Dorsal Root Ganglia (Sensory, Somatic)

    Afferent Nerve Fibers

  • 82

    Ganglia associated with______contain Autonomic Motor Neurons -Autonomic Ganglia (Motor, Visceral)

    Efferent Nerve Fibers

  • 83

    Mature neurons are

    amitotic

  • 84

    if the soma (cell body) of the damaged nerve is intact, the _____ may regenerate in PNS; does not occur in CNS

    peripheral axon

  • 85

    never regenerate

    CNS Axons

  • 86

    can regenerate if damage is not severe

    PNS Axons

  • 87

    CNS ______ bear growth-inhibiting proteins that prevent CNS fiber regeneration

    oligodendrocytes

  • 88

    at injury site form scar tissue

    Astrocytes

  • 89

    neutralizing growth inhibitors, blocking receptors for inhibitory proteins, destroying scar tissue components

    Treatment: CNS Axons: never regenerate

  • 90

    can regenerate if damage is not severe

    PNS Axons

  • 91

    Axon fragments & myelin sheaths distal to injury degenerate (_______); spreads down axon

    Wallerian degeneration

  • 92

    ______clean dead axon debris; Schwann cells are stimulated to divide

    Macrophages

  • 93

    grow through regeneration tube

    Axon filaments

  • 94

    & new myelin sheath forms

    Axon regenerates,

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    問題一覧

  • 1

    PNS provides links from & to world outside our body

    Consists of all neural structures outside brain & spinal cord that can be broken down into four parts

  • 2

    PNS provides links from & to world outside our body

    Part 1 – Sensory Receptors, Part 2 – Transmission Lines: Nerves & Their Structure & Repair, Part 3 – Motor Endings & Motor Activity, Part 4 – Reflex Activity

  • 3

    specialized to respond to changes in environment (stimuli)

    Sensory Receptors

  • 4

    Activation results in graded potentials that trigger nerve impulses

    Sensory Receptors

  • 5

    Three ways to classify receptors:

    type of stimulus, body location, structural complexity

  • 6

    respond to touch, pressure, vibration, & stretch

    Mechanoreceptors

  • 7

    sensitive to changes in temperature

    Thermoreceptors

  • 8

    respond to light energy (example: retina)

    Photoreceptors

  • 9

    respond to chemicals (examples: smell, taste, changes in blood chemistry)

    Chemoreceptors

  • 10

    sensitive to pain-causing stimuli (examples: extreme heat or cold, excessive pressure, inflammatory chemicals)

    Nociceptors

  • 11

    Respond to stimuli arising outside body –Receptors in skin for touch, pressure, pain, & temperature –Most special sense organs

    Exteroceptors

  • 12

    Respond to stimuli arising in internal viscera & blood vessels –Sensitive to chemical changes, tissue stretch, & temperature changes –Sometimes cause discomfort but usually person is unaware of their workings

    Interoceptors (Visceroceptors)

  • 13

    Respond to stretch in skeletal muscles, tendons, joints, ligaments, & connective tissue coverings of bones & muscles –Inform brain of one's movements

    Proprioceptors

  • 14

    Modified dendritic endings of sensory neurons ●Are found throughout body & monitor most types of general sensory information –General Senses: Tactile Sensations (Touch, Pressure, Stretch, Vibration), Temperature, Pain, & Muscle Sense •No “one-receptor-one-function” relationship •Receptors can respond to multiple stimuli

    Simple receptors of the General Senses

  • 15

    All are housed in complex sense organs –Vision, Hearing, Equilibrium, Smell, & Taste

    Receptors for Special Senses

  • 16

    Most are Non-Myelinated & abundant in epithelia/connective tissues –Respond mostly to temperature, pain, or light touch

    Non-Encapsulated (free) Nerve Endings

  • 17

    Located in superficial Dermis –Cold receptors are activated by temps from 10 to 40C –Heat receptors are activated from 32 to 48C located in in deeper dermis •Outside those temperature ranges, nociceptors are activated & interpreted as pain

    Thermoreceptors

  • 18

    pain receptors triggered by extreme temperature changes, pinch, or release of chemicals from damaged tissue –Vanilloid receptor: protein in nerve membrane is main player •Acts as ion channel that is opened by heat, low pH, chemicals (example: capsaicin in red peppers) •Itch receptors in dermis: can be triggered by chemicals such as histamine

    Nociceptors

  • 19

    Non-Encapsulated (Free) Nerve Endings (2answers)

    Tactile (Merkel) Discs, Hair Follicle Receptors

  • 20

    function as light touch receptors ●Located in deeper layers of epidermis

    Tactile (Merkel) Discs

  • 21

    free nerve endings that wrap around hair follicles ●Act as light touch receptors that detect bending of hairs –Ex: Allows you to feel a mosquito landing on your skin

    Hair Follicle Receptors

  • 22

    Most body tissues; most dense in connective tissues (ligaments, tendons, dermis, joint capsules, periostea) and epithelia (epidermis, cornea, mucosae, and glands)

    Free nerve endings of sensory neurons

  • 23

    Basal layer of epidermis

    Modified free nerve endings: Epithelial tactile complexes (Merkel cells and discs)

  • 24

    Surrounding hair follicles

    Hair follicle receptors

  • 25

    Encapsulated Dendritic Endings (2answers)

    Tactile (Meissner’s) corpuscles, Lamellar (Pacinian) corpuscles

  • 26

    Almost all (Encapsulated Dendritic Endings) are _______ whose terminal endings are encased in _______

    Mechanoreceptors, connective tissue capsule

  • 27

    Almost all are Mechanoreceptors whose terminal endings are encased in connective tissue capsule

    Encapsulated Dendritic Endings

  • 28

    small receptors involved in discriminative touch –Found just below skin, mostly in sensitive & hairless areas (fingertips)

    Tactile (Meissner’s) corpuscles

  • 29

    large receptors respond to deep pressure & vibration when first applied (then turn off) –Located in deep dermis

    Lamellar (Pacinian) corpuscles

  • 30

    respond to deep & continuous pressure - Located in dermis

    Bulbous Corpuscles (Ruffini Endings)

  • 31

    spindle-shaped proprioceptors that respond to muscle stretch

    Muscle Spindles

  • 32

    proprioceptors located in tendons that detect stretch

    Tendon Organ

  • 33

    proprioceptors that monitor joint position & motion

    Joint Kinesthetic Receptors

  • 34

    Dermal papillae of hairless skin, particularly nipples, external genitalia, fingertips, soles of feet, eyelids

    Tactile (Meissner's) corpuscles

  • 35

    Dermis and hypodermis; periostea, mesentery, tendons, ligaments, joint capsules; most abundant on fingers, soles of feet, external genitalia, nipples

    Lamellar (Pacinian) corpuscles

  • 36

    Survival depends upon ____ & ____.

    Sensation, Perception

  • 37

    awareness of changes in the internal & external environment

    Sensation

  • 38

    the conscious interpretation of those stimuli

    Perception

  • 39

    part of sensory system serving body wall & limbs

    Somatosensory System

  • 40

    Input is relayed _____ head, but processed along the way

    toward

  • 41

    Somatosensory System: part of sensory system serving body wall & limbs •Receives inputs from

    Exteroceptors, Proprioceptors, Interoceptors

  • 42

    (Somatosensory System) Levels of neural integration in sensory systems: (3answers)

    Receptor level, Circuit level, Perceptual level

  • 43

    sensory receptors

    Receptor level

  • 44

    processing in ascending pathways

    Circuit level

  • 45

    processing in cortical sensory areas

    Perceptual level

  • 46

    (Processing at the Receptor Level) For sensation to occur, the stimulus must excite a receptor, & the AP must reach CNS

    Generating a signal

  • 47

    Stimulus energy must match receptor specificity (touch receptors do not respond to light) ●Stimulus must be applied within receptive field

    Generating a signal

  • 48

    must occur—energy of stimulus is converted –Generator Potential (in general receptors) or receptor potential (in special sense receptors): graded potential •Graded potentials must reach threshold → AP

    Transduction

  • 49

    Change in sensitivity in presence of constant stimulus

    Adaptation

  • 50

    -Receptor membranes become less responsive -Receptor potentials decline in frequency or stop

    Adaptation

  • 51

    fast-adapting, send signals at beginning or end of stimulus ●Ex: receptors for pressure, touch, & smell

    Phasic Receptors

  • 52

    slow adapting or not at all ●Ex: nociceptors & most proprioceptors

    Tonic Receptors

  • 53

    Pathways of 3 neurons conduct sensory impulses from receptors upward to appropriate cortical regions

    Processing at the Circuit Level

  • 54

    Processing at the Circuit Level –Pathways of 3 neurons conduct sensory impulses from receptors upward to appropriate cortical regions (3answers)

    First-Order Sensory Neurons, Second-Order Sensory Neurons, Third-Order Sensory Neurons

  • 55

    Conduct impulses from receptor level to spinal reflexes or second-order neurons in CNS

    First-Order Sensory Neurons

  • 56

    Transmit impulses to third-order sensory neurons

    Second-Order Sensory Neurons

  • 57

    Conduct impulses from thalamus to the somatosensory cortex (perceptual level)

    Third-Order Sensory Neurons

  • 58

    Interpretation of sensory input depends on specific location of target neurons in sensory cortex

    Processing at the Perceptual Level

  • 59

    ability to detect a stimulus (requires summation of impulses)

    Perceptual Detection

  • 60

    ●Felt as vague aching, gnawing, burning ●Activated by tissue stretching, ischemia, chemicals, muscle spasms

    Visceral Pain - visceral organ receptors

  • 61

    pain from one body region perceived as coming from different region ●Visceral & Somatic Pain fibers travel along same nerves, so brain assumes stimulus comes from common (somatic) region –Ex: left arm pain during heart attack

    Referred Pain

  • 62

    Long-lasting or intense pain, such as limb amputation, can lead to __(1)__ (pain amplification), chronic pain, & ___(2)___

    (1) Hyperalgesia, (2) Phantom Limb Pain

  • 63

    receptors are activated by long-lasting or intense pain

    NMDA

  • 64

    pain felt in limb that has been amputated –Now use epidural anesthesia during surgery to reduce phantom pain

    Phantom Limb Pain

  • 65

    cordlike organ of PNS

    Nerve

  • 66

    Bundle of myelinated & nonmyelinated peripheral axons enclosed by

    connective tissue

  • 67

    Two types of nerves:____or ____depending on where they originate

    spinal, cranial

  • 68

    Endoneurium/Neurilemma

    loose connective tissue that encloses axons & their myelin sheaths (Schwann cells)

  • 69

    Perineurium

    coarse connective tissue that bundles fibers into Fascicles

  • 70

    Epineurium

    tough fibrous sheath around all fascicles to form the nerve

  • 71

    contain both sensory & motor fibers ●Impulses travel both to & from CNS

    Mixed Nerves

  • 72

    impulses only toward CNS

    Sensory (Afferent) Nerves

  • 73

    impulses only away from CNS

    Motor (Efferent) Nerves

  • 74

    are rare; most nerves are mixed

    Pure Sensory (Afferent), Pure Motor (Efferent) Nerves

  • 75

    Types of fibers in______ -Somatic Afferent (sensory from muscle to brain) -Somatic Efferent (motor from brain to muscle) -Visceral Afferent (sensory from organs to brain) -Visceral Efferent (motor from brain to organs)

    Mixed Nerves

  • 76

    sensory from muscle to brain

    Somatic Afferent

  • 77

    motor from brain to muscle

    Somatic Efferent

  • 78

    sensory from organs to brain

    Visceral Afferent

  • 79

    motor from brain to organs

    Visceral Efferent

  • 80

    contain neuron cell bodies associated with nerves in PNS

    Ganglia

  • 81

    Ganglia associated with _____contain cell bodies of Sensory Neurons -Dorsal Root Ganglia (Sensory, Somatic)

    Afferent Nerve Fibers

  • 82

    Ganglia associated with______contain Autonomic Motor Neurons -Autonomic Ganglia (Motor, Visceral)

    Efferent Nerve Fibers

  • 83

    Mature neurons are

    amitotic

  • 84

    if the soma (cell body) of the damaged nerve is intact, the _____ may regenerate in PNS; does not occur in CNS

    peripheral axon

  • 85

    never regenerate

    CNS Axons

  • 86

    can regenerate if damage is not severe

    PNS Axons

  • 87

    CNS ______ bear growth-inhibiting proteins that prevent CNS fiber regeneration

    oligodendrocytes

  • 88

    at injury site form scar tissue

    Astrocytes

  • 89

    neutralizing growth inhibitors, blocking receptors for inhibitory proteins, destroying scar tissue components

    Treatment: CNS Axons: never regenerate

  • 90

    can regenerate if damage is not severe

    PNS Axons

  • 91

    Axon fragments & myelin sheaths distal to injury degenerate (_______); spreads down axon

    Wallerian degeneration

  • 92

    ______clean dead axon debris; Schwann cells are stimulated to divide

    Macrophages

  • 93

    grow through regeneration tube

    Axon filaments

  • 94

    & new myelin sheath forms

    Axon regenerates,